Traditional Circuit Switched (CS) telecommunication networks, such as Public Switched Telecommunication Network (PSTN) or Integrated Services Digital Network (ISDN) have been supplemented by Public Land Mobile Networks (PLMN) implemented as e.g. a Global System for Mobile communications (GSM), Wideband—Code Division Multiple Access (W-CDMA) or Time Division—Synchronous Code Division Multiple Access (TD-SCDMA). The PLMN networks do nowadays also support Packet Switched (PS) telecommunication for e.g. establishing Internet Protocol (IP) connections, allowing enriched communication such as voice and video.
Voice calls, regarded as a traditional communication method, provide a level of interactive communication, however video as medium took off as a higher level and more sophisticated way of communication.
Standards, such as the 3G-324M adopted by the 3rd. Generation Partnership Project (3GPP), have been defined to support conversational Multi-Media over CS networks. The International Engineering Task Force (IETF) has defined a Session Initiation Protocol (SIP) to support Multi-Media calls to be initialized over IP based PS networks.
When a called party answers a 3G-324M video telephony call setup on its terminal both a video channel and an audio channel are established after a call setup.
If the called party does not have hands-free enabled, the loud-speaker in the terminal of the called party will be activated, play out audio from the calling party, and audio captured from the terminal of the called party will be sent over an audio channel to the terminal of the called party.
The camera in the terminal of the called party (e.g. a front camera at a mobile phone) will be activated when the call setup is answered and the captured video is sent to the terminal of the calling party via the video channel.
However, the arrival of the more sophisticated way of communication by video also has a disadvantage in that the privacy of the called party when answering a video call setup incurs a risk. When a video call setup is answered in a non-private area, the video screen might disclose a scene, that is not intended for others. The same remark is valid for the automatic launch of the camera at the terminal of the called party, possibly providing the calling party with a private scene of the called party.
As to benefit from video capabilities of the terminal a called party might adapt configuration options or settings of the terminal in relation to a current privacy situation.
Even if the called party is familiar with the configuration options of the terminal for an incoming video call setup, there might be situations which do not allow the user, or at least allow fast enough, to adapt the configuration options of the terminal, possibly resulting in a privacy intrusion.
Additionally, the automatic launch of the loud-speaker in the terminal of the called party, as provided by the 3G-324 standard, might be non desired when answering a video call in a non private area. Without a hands-free device and in a common case a call setup is answered without checking if is a video call setup and the automatic launch of the loudspeaker becomes intrusive.
The personal intrusion problem that the implementation of video calls causes is regarded as a barrier for the growth of video telephony.